We woke up Wednesday morning with our thoughts and prayers directed at Cape Canaveral, Fla., where the United States was scheduled to get back into the space race after a 2-year hiatus.

However, it turned out to be a familiar problem for a NASA program that had hoped to begin its new space shuttle mission on a positive note.

After all the painstaking effort to cover every detail, and well more than $1 billion spent on new safety features, NASA pulled the plug on the launch of Discovery less than an hour and a half away from liftoff Wednesday afternoon. A fuel gauge that said full when it meant empty was the same type of problem the space agency saw during a test in April.

More than three decades ago - shortly after some Apollo and Soyuz astronauts shook hands miles above the earth and the Cold War - NASA shifted its gears away from monstrous moon rockets to a reusable space craft. The fleet of space shuttles - after Columbia was the first to lift off launch pad 39B in the early 1980s - grew to Atlantis, Challenger, Discovery, Endeavor and Enterprise. They were so impressive, the USSR built a reusable rocket of its own that looked mighty similar to our shuttles but never lifted off Soyuz rocket launch pads.

Shuttle launches were becoming routine, possibly too routine, until we lost Challenger in 1986. Then, we lost Columbia in 2003. Fourteen astronauts gave their lives to do what only a few have done in our four-decade history of space flight.

Is still using the space shuttles worth the risks, all the costs? They have not only hauled up what is now the International Space Station, but also put into space and gone back to repair the Hubble Telescope, which has given us a man-made look into lightyears of our galaxy and universe.

However, we also know the shuttles that remain are 20 years old. It would cost billions - in addition to the $1.4 billion it costs every time a shuttle mission is planned and executed, not to mention the billions spent since 2003 to make the shuttle ready for flight again - to create a new space vehicle.

Wednesday's launch scrub cost NASA an estimated $616,000 in fuel and labor costs. Discovery could sit on the launch pad until at least Saturday, and the postponement could last much longer, depending on the repairs needed.

Just the night before, a window cover slipped off and damaged the shuttle's fragile thermal tiles while it was still on the launch pad, but NASA said Discovery was still good to go Wednesday.

While NASA is scheduled to continue the shuttle program until 2010 - a deadline given by President Bush after the Columbia tragedy - we can at least be satisfied the space agency's safety culture has changed and isn't taking even a faulty sensor lightly this time.